1. Field of the Invention
The present invention relates to a control system and/or method for sensing faulty solenoids. In particular, the present invention relates to a control system and/or method for sensing faults in the solenoids of solenoid-controlled actuators for vehicular automated or semi-automated change gear transmission systems.
2. Description of the Prior Art
Change-gear mechanical transmissions are well known in the prior art, as may be seen by reference to U.S. Pat. Nos. 3,105,395; 3,335,616; 4,428,469; 4,754,665; 4,920,815; 4,944,197; 5,086,897; 5,370,013; and 5,390,561, the disclosures of which are incorporated herein by reference. Two-position and three-position, fluid-actuated, actuator piston assemblies and actuator systems associated therewith also are well known in the prior art, as may be seen by reference to U.S. Pat. Nos. 4,899,607; 4,928,544; 4,936,156; 5,054,591; 5,193,410; 5,263,379; 5,272,441; 5,329,826; 5,651,292; and 5,661,998, the disclosures of which are incorporated herein by reference.
Transmission systems of particular reference are disclosed in the following patent applications, the disclosures of which are incorporated herein by reference:
Ser. No. 09/178,346 filed Oct. 22, 1998 entitled "ROBUST CONTROL FOR THREE-POSITION TRANSMISSION SHIFT ACTUATOR ASSEMBLY" PA1 Ser. No. 08/053,089 filed Apr. 1, 1998 entitled "RANGE SHIFT CONTROL" PA1 Ser. No. 08/053,090 filed Apr. 1, 1998 entitled "ADAPTIVE NEUTRAL SENSING" PA1 Ser. No. 08/053,091 filed Apr. 1, 1998 entitled "JAW CLUTCH ENGAGEMENT CONTROL FOR ASSISTED, MANUALLY SHIFTED, SPLITTER-TYPE TRANSMISSION SYSTEM" PA1 Ser. No. 08/053,092 filed Apr. 1, 1998 entitled "ENGINE FUEL CONTROL FOR COMPLETING SHIFTS IN CONTROLLER-ASSISTED, MANUALLY SHIFTED TRANSMISSIONS" PA1 Ser. No. 08/053,093 filed Apr. 1, 1998 entitled "ADAPTIVE UPSHIFT JAW CLUTCH ENGAGEMENT CONTROL" PA1 Ser. No. 08/053,095 filed Apr. 1, 1998 entitled "DYNAMIC RANGE SHIFT ACTUATION" PA1 Ser. No. 08/053,181 filed Apr. 1, 1998 entitled "ADAPTIVE SPLITTER ACTUATOR ENGAGEMENT FORCE CONTROL" PA1 Ser. No. 08/902,603 filed Aug. 7, 1997 entitled "PARTIALLY AUTOMATED, LEVER-SHIFTED MECHANICAL TRANSMISSION SYSTEM" PA1 Ser. No. 08/990,678 filed Dec. 15, 1997 entitled "ASSISTED LEVER-SHIFTED TRANSMISSION"
Controls for automated and semi-automated transmission systems, including fault detection systems and/or methods, are known in the prior art as may be seen by reference to U.S. Pat. Nos. 4,595,986; 4,702,127; 4,922,425; 4,888,577; 4,849,899; and 5,272,441, the disclosures of which are hereby incorporated by reference.
It is known that solenoid-related faults sometimes occur in the solenoid-controlled actuators used in vehicular transmission systems. If such a fault occurs, it is highly desirable to indicate such a condition to the operator of the vehicle, and to initiate some safe form of recovery logic and/or temporary mode of operation. These actions will notify the operator that correction action is required, and will minimize the possibility of the transmission suffering mechanical damage or behaving in an unintended manner.
In order to properly respond to a solenoid-related fault, a reliable fault detection system must be implemented. Although examples of fault detection systems can be found in the prior art, such systems typically are complicated, cannot detect a wide variety of solenoid-related faults, or cannot reliably be implemented in all transmission control configurations. One particular problem with the prior art fault detection systems is their inability to be reliably implemented in low side solenoid driver circuit configurations, such configurations being desirable in that they enable a less complicated and lower cost electronic control unit to be used in the transmission control.